Thin Film Heater

Abstract

A method of fabricating a thin film heater includes a first step of etching a metal sheet from two opposing sides to provide a planar heating element; and a second step of attaching the heating element to a flexible electrically insulating backing film. The method allows for the fabrication of a thin film heater which provides more uniform heating and allows for greater range of selection of the properties of the flexible electrically insulating backing film and the parameters of the etching process. A heater assembly and an aerosol generating device incorporating the thin film are also described.

1 . A method of fabricating a thin film heater comprising:
 etching a metal sheet from two opposing sides to provide a planar heating element; and   attaching the planar heating element to a flexible electrically insulating backing film.   
     
     
         2 . The method of  claim 1 , wherein the etching step comprises photoetching the metal sheet. 
     
     
         3 . The method of  claim 1 , wherein the planar heating element is attached to a surface of the flexible electrically insulating backing film using an adhesive. 
     
     
         4 . The method of  claim 1 , wherein the etching step comprises etching the metal sheet to provide two or more connected heating elements. 
     
     
         5 . The method of  claim 1 , wherein the etching step comprises etching the metal sheet to provide two or more connected heating elements supported within a support frame. 
     
     
         6 . The method of  claim 4 , further comprising:
 detaching each of the two or more connected heating elements and attaching each of the two or more connected heating elements to a corresponding piece of the flexible electrically insulating backing film.   
     
     
         7 . The method of  claim 4 ,
 wherein the attaching step includes attaching the two or more connected heating elements to a common flexible electrically insulating backing film; and   further comprising cutting the common flexible electrically insulating backing film between the two or more heating elements to provide multiple assemblies comprising a single heater element attached to a flexible backing film.   
     
     
         8 . The method of  claim 1 , wherein the etching step comprises etching the metal sheet to form a-the planar heating element comprising:
 a heater track which follows a circuitous path covering a heating area within a plane of the planar heating element; and   two extended contact legs for connection to a power source.   
     
     
         9 . The method of  claim 8 , wherein a length of the two extended contact legs is substantially equal to or greater than dimensions of the heating area. 
     
     
         10 . The method of  claim 8 , further comprising:
 attaching a second flexible film layer so as to enclose the heater track between the flexible electrically insulating backing film and the second flexible film layer.   
     
     
         11 . The method of  claim 10 , wherein the second flexible film layer comprises a heat shrink material. 
     
     
         12 . The method of  claim 1 , wherein the flexible electrically insulating backing film comprises polyimide. 
     
     
         13 . The method of  claim 1 , wherein the flexible electrically insulating backing film comprises PTFE. 
     
     
         14 . The method of  claim 1 , wherein the flexible electrically insulating backing film has a thickness of less than 50 μm. 
     
     
         15 . A thin film heater fabricated by the method of  claim 1 .